package com.test;

import java.util.StringJoiner;

public class Stringbulder {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder();
        sb.append(16);
        String s = sb.toString();
        System.out.println(sb);
        char c = sb.charAt(1);
        System.out.println(c);
        int i = c - 48;
        System.out.println(i);

        StringJoiner sj = new StringJoiner(",","[","]");
        sj.add("aaa").add("bbb").add("ccc");
        System.out.println(sj);
        String s2 = sj.toString();
    }
}
